Fasting causes competition for nutrients between mother and fetus. The rate of maternal protein degradation may be lower in pregnancy in order to protect maternal stores will supplying the fetus. This rate will be measured by constant maternal infusion of I-13C leucine with application of steady state isotope dilution methods & will be compared in pregnancy and Disturbance of the control of protein degradation may be responsible for altered fetal growth rate in gestational diabetes and preeclampsia. grant=M01RR000550549 Abnormal postprandial metabolism of lipids and lipoproteins is potentially atherogenic. We plan to study this phenomenon in obese subjects, non-insulin dependent diabetic subjects, insulin-dependent diabetics, and subjects with low HDL cholesterol and to compare the changes in the above groups with age, sex and weight matched normal controls.